VMS (Vessel Monitoring System) is a satellite surveillance system primarily used to monitor the location and movement of commercial fishing vessels. The system uses satellite-based communications from on-board transceiver units, which certain vessels are required to carry. The transceiver units send position reports that include vessel identification, time, date, and location, and are mapped and displayed on the end user’s computer screen.

Each vessel typically sends position reports once an hour, but increases intervals when the vessel is approaching an environmentally sensitive area. Alerts can be sent to the VMS technicians and other personnel when a particular vessel location might require additional inquiry or contact with the vessel operator.